Line a 10 by 15 inch pan with wax paper. Melt 1 1/2 cups of the chocolate and spread it over the wax paper. It won’t reach all the way to the edge of the pan. Put it in the refrigerator to set.
Combine the peanut butter, powdered sugar, and butter. I put mine in the microwave during mixing for 10 to 15 seconds to help with mixing. Spread it over the chocolate layer evenly. Put the pan back in the refrigerator to set.
Melt the remaining 2 cups chocolate chips and then spread over the peanut butter layer. Top with the Reese’s Pieces. Let set and then break apart. Store in an airtight container.